On 3rd-and-goal early in the second quarter, Michael Crabtree, alone in the left corner of the end zone, waved his arms in frustration as he watched quarterback Alex Smith, looking in the opposite direction, throw incomplete to running back Frank Gore.

By the end of the game, Crabtree, with a white towel over his head and his twice-broken left foot throbbing, was far more subdued.

The wide receiver who had foot surgery in July couldn't finish San Francisco's 33-17 victory over the Seahawks on Sunday. He had one catch for 4 yards. Coach Jim Harbaugh noticed him limping early in the third quarter, and Crabtree watched the rest of the game from the sideline.

He had X-rays after the game, which were negative. Crabtree conceded he was relieved - his foot was so painful he feared he might have re-broken it.

"It's not totally healed," Crabtree said. "But it's good enough for me to go out there and play ... It was hurting so bad, I was concerned."

Crabtree said his foot didn't hurt after practices this week, but it was affected during game conditions.

The Dallas native said he expected to play next week against the Cowboys. And he acknowledged that he needed to clean up his end-zone decorum.

"I shouldn't have done that," Crabtree said when asked about waving his arms in frustration. "I'm just so competitive, man. I had a touchdown. I kind of spazzed out a little bit on that play."

Defensive letdown: After limiting a seemingly hopeless Seahawks offense to three first downs (one via penalty), 37 yards and zero points in the first half, linebacker Patrick Willissaid the Niners relaxed a bit.

The Seahawks, who didn't cross midfield in the first two quarters after their first drive, opened the third quarter on a nine-play, 56-yard drive capped by Tarvaris Jackson's 8-yard touchdown to Golden Tate.

"Our intensity wasn't there that first series," Willis said. "But we picked it up as pros have to do, because if you're not, things like that can happen. It was a good wake-up call for us."